The memory controller of this type conventionally proposed controls a ferroelectric random access memory (FeRAM), which is a non-volatile random access memory that retains its storing data even when the power is turned off and works as a cache memory, and a hard disk drive (HDD) such that data from personal computer systems can be stored in the FeRAM and HDD (see for example Non-Patent Literature 1, “A 128 Mb ChainFeRAMTM and System Designs for HDD Application and Enhanced HDD Performance”, by Daisaburo Takashima et al.). This type of controller has eliminated the need to periodically save the data stored in a FeRAM to an HDD in preparation for unexpected power shutdown, and thus increased the amount of data to be stored in the FeRAM and improved the cache hit ratio.